JP2007187630A - Method and apparatus for detecting flaw of pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To recognize whether the flaw of the pattern of the TFT circuit on a glass substrate, which is used in a flat panel type display, such as a liquid crystal display, a plasma display, an organic EL device, etc., is a short flaw or an open flaw, when foreign matters are bonded to a substrate. <P>SOLUTION: The reflected illumination light 34, from a reflecting light source 33, is guided to the panel 31 on a stage 30 by a half mirror 32 and the reflected light from the panel 31 is captured by a first imaging camera 38. The transmitted observation image of a panel 31 is fetched by the transmitted light 43, from a transmission light source 42 on the under side of the stage 30, and the transmitted observation image is captured by a second imaging camera 37 through the half mirror 32. The image signal from a first imaging camera 38 and the image signal from a second imaging camera 37 are processed by an image control unit 39, to discriminate whether the pattern is a short flaw or an open flaw, when a foreign matter is bonded to the substrate 31. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pattern defect detection method and a pattern defect detection apparatus, and more particularly to a pattern defect detection method and a pattern defect detection apparatus for detecting a pattern defect formed on a transparent or translucent panel.

  Instead of CRT (Cathode Ray Tube), a flat panel display tends to be used. Examples of such a thin flat panel display (FPD, Flat Panel Display) include a liquid crystal display (LCD, Liquid Crystal Display), a plasma display, an organic EL display (OELD, Organic Electroluminescence Display), and the like. Some of these displays use a TFT substrate in which a glass plate is mainly used as a substrate and a semiconductor element called TFT (Thin Film Transistor) is formed in a drive circuit. The TFT substrate is obtained by forming a TFT circuit and a wiring pattern from a wiring material or a semiconductor material formed by a technique called sputtering or CVD (Chemical Vapor Deposition) using a semiconductor process called photolithography.

  When forming a pattern on a TFT substrate, if a missing pattern (white defect) or an extra residue (black defect), which is generally called a defect, is caused by a foreign substance called dust, circuit breakage of the pattern or A short circuit occurs, and the TFT circuit does not function. In order to detect this defect and the foreign substance that causes the defect, an optical defect inspection is performed.

  A general defect inspection configuration is that a glass plate to be inspected is placed on an XYZ stage, the substrate is irradiated with a reflection light source, and reflected light obtained from a predetermined position of the substrate is taken into an inspection camera. Thus, the pattern image is acquired. A CCD area sensor, a CCD line sensor, TDI, or the like is used for the inspection camera, and the obtained image information is developed by the image processing unit for inspection. For the inspection at this time, an adjacent comparison inspection using a basic block and peripheral blocks and a comparison method with a reference image are used, and a portion having a difference of a certain intensity level or more is determined as a defect.

  In addition to the reflected light inspection, there are proposed a transmitted light inspection using transmitted light and a method of inspecting by irradiation using both reflected light and transmitted light (Japanese Patent Laid-Open No. 2001-305074). ing. By this method, it becomes possible to detect not only a defect detected only by reflected light and a defect detected only by transmitted light, but also a defect that could not be detected by each. However, since the above inspection method is an inspection method that assumes defects in the same film as the pattern, there is a problem that the types of detected defects cannot be classified.

  Conventionally, the detected defect is generally used as a management index for a process or a specific facility by monitoring the number of defects. Recently, in order to improve the yield of panels, there are increasing cases of repairing (repairing) defects. In order to perform the repair, the operator needs to perform a classification operation to see the defect image and discriminate the type from experience and knowledge. If this classification is mistaken or defects that do not need to be repaired are sent to the repair process, the efficiency is lowered. In other words, whether or not defects can be properly classified affects repair efficiency.

  The classification work is performed using the acquired image data. Here, a method for acquiring image data will be described. Defects detected by the defect inspection apparatus are enlarged and observed using a review apparatus or the like with improved inspection magnification. For example, a review image acquisition method in the case of an inspection / review integrated device will be described. The reflected light obtained from the substrate is introduced into the inspection camera, and an image of the defect is acquired. The defect information obtained here includes defect position information and defect size. A defect classifies an image obtained at the time of inspection into an arbitrary type. Alternatively, classification is performed by an automatic defect classification program that automatically classifies defects from images at the time of inspection.

  The visual field size at the time of inspection has a long side of, for example, 10 to 60 mm. At this time, if the size of the defect to be detected is 5 μm, for example, it is as small as 1/2000 to 1/12000 with respect to the visual field size. Have difficulty. Therefore, in order to improve the defect classification accuracy, an enlarged image of the defect can be acquired by observing (reviewing) the field size with a long side of, for example, 0.25 to 0.1 mm. The form of the defect can be easily understood from the magnified image, and the classification accuracy can be improved.

  However, only the reflected light image can be used to determine whether the pattern under the foreign object is broken or short-circuited, or just a foreign object is attached when a foreign object is attached to the pattern. I could not. In particular, when a foreign object adheres to the pattern and a defect occurs that changes the color of part of the surface of the pattern, there is a problem that it is not possible to determine whether the pattern shape is defective or the foreign object is attached. It was.

In addition to the reflected light image, there is a method to obtain an image by simultaneously irradiating both the transmitted light image obtained by using transmitted light and the reflected light / transmitted light. Although it can be recognized as a defect, since the positional relationship of the defect in the Z direction (the film thickness direction of the pattern) is not clear, there is a problem that it cannot be classified as a foreign object.
JP 2001-305074 A JP 2004-101194 A

  An object of the present invention is to provide a pattern defect detection method and a detection apparatus that can reliably detect a pattern defect formed on a transparent or translucent panel.

  Another object of the present invention is to provide a pattern defect detection method and a detection apparatus capable of identifying whether a pattern is a short defect or an open defect when a foreign object adheres to the pattern of a transparent or translucent panel. It is.

  Still another object of the present invention is to provide a pattern defect detection method and a detection apparatus which can use the inspection result for the processing of the process prior to the detection of the defect or the management of the apparatus. is there.

  Still another object of the present invention is to provide a pattern defect detection method and detection apparatus which can use the inspection result for correcting or removing pattern defects and foreign matters.

  The above-described problems and other problems of the present invention will be made clear by the technical idea of the present invention described below and the embodiments thereof.

The main invention of the present application is a pattern defect detection method for detecting a pattern defect formed on a transparent or translucent panel.
The present invention relates to a pattern defect detection method, characterized in that the type of defect of the pattern is specified using image data based on reflected light and image data based on transmitted light at a position where a defect is found.

Another main invention of the present application is a pattern defect detection method for detecting a pattern defect formed on a transparent or translucent panel.
Acquire image data by reflected light at a position where a defect is found, then acquire image data by transmitted light at that position, acquire image data by transmitted light at a position where there is no defect, and transmit the transmitted light at the defect position. The pattern defect detection method is characterized in that the type of defect of the pattern is specified by comparing the image data obtained by the above and image data obtained by transmitted light at a position where there is no defect.

  Here, in the comparison with the image data by the transmitted light at the position where there is no defect, when the corresponding pattern is not continuous with the same gradation, it may be determined that the short circuit is not short-circuited. Further, in the comparison with the image data by the transmitted light at the position where there is no defect, if the corresponding pattern is continuous with the same gradation, it may be short-circuited. Further, in the comparison with the image data by the transmitted light at the position where there is no defect, when the corresponding pattern is divided, it may be disconnected. In addition, it is determined whether or not there is a foreign object on the panel from the image data of the reflected light, and a short circuit and a disconnection are determined for each of the case where it is determined that there is a foreign object and the case where there is no foreign object. Good.

  Further, the determination as to whether or not there is a foreign object may be made by comparison with a foreign object database. Further, the short circuit may be determined by comparison with a short defect database. The disconnection may be determined by comparison with an open defect database. When it is determined that there is a foreign object in the determination of whether there is a foreign object, a block of a pattern is created with a predetermined gradation, and it is determined whether there is a non-continuous part from the outline of the block. If there is a part, it is judged as a disconnection. If there is no discontinuous part, it is judged as a short circuit when the pattern wiring is connected to each other, and a foreign object is found when the pattern wiring is not connected to each other. You may judge that there is. Further, the detection result may be used for processing in a process prior to pattern defect detection or for management of the apparatus. The detection result may be used to correct or remove pattern defects and foreign matter.

The main invention related to the inspection apparatus is a hollow, transparent, or translucent stage on which a transparent or translucent panel on which a pattern is formed is placed;
A reflective light source for irradiating the panel with reflected light on the surface;
A transmissive light source for irradiating the panel with transmitted light through the stage;
First imaging means for capturing a reflected image irradiated with reflected light from the reflected light source;
A second imaging means for capturing a transmitted image transmitted by transmitted light from the transmitted light source;
An image control unit that receives the video signal from the first imaging unit and the video signal from the second imaging unit and processes these two types of video signals;
The present invention relates to a pattern defect detection apparatus having a pattern.

  Here, it is preferable that the stage is made of glass that transmits light and can be adjusted in position in the X-axis direction, the Y-axis direction, and the Z-axis direction. The reflected light source may be disposed above the stage, and the transmitted light source may be disposed below the stage. The reflected light and transmitted light from the panel may be guided to the first imaging unit and the second imaging unit, respectively, by a half mirror.

  The preferable aspect of this invention is related with the improvement of the acquisition image acquisition method for classifying a defect (pattern shape defect) and adhering foreign material more reliably than before, and the classification method of a defect. Here, in particular, the defect type detected by the inspection apparatus is compared with the image data acquired with the reflected light and the image data acquired with the transmitted light to identify the type of the defect. The types of defects specified here are foreign matters, white defects (such as open defects), and black defects (such as short defects). In particular, foreign matters and other defects are classified. In addition, using the data obtained by the above classification, the process and apparatus of the process before the inspection are managed. Further, the defect and foreign matter are corrected or removed using the classified data.

  According to such an aspect, when a foreign substance is attached to the panel, it is possible to identify whether the pattern is a short defect or an open defect. And when repairing a defect, the defect of the repair object can be narrowed down by said identification, a check of a useless defect can be reduced, and a tact time can be aimed at. In addition, when it is determined that the adhering matter is only foreign matter, the specific foreign matter can be managed by monitoring the same type of defect (foreign matter). From the fluctuation, it is possible to grasp the deterioration of the apparatus and the process, suppress the yield reduction, and improve the efficiency.

  In a pattern defect detection method for detecting a defect in a pattern formed on a transparent or translucent panel, the main invention of the present application acquires image data based on reflected light at a position where the defect is found, and Acquire image data based on transmitted light, acquire image data based on transmitted light at a position where there is no defect, compare image data based on transmitted light at a position where the defect is located, and image data based on transmitted light at a position where there is no defect. The type of defect is specified.

  According to such a pattern defect detection method, pattern defect detection is accurately identified by comparing image data obtained by transmitted light at a defect position with image data obtained by transmitted light at a position where there is no defect.

  The main invention related to the defect detection apparatus is a hollow, transparent, or translucent stage on which a transparent or translucent panel with a pattern is placed, and a reflection that irradiates the surface with reflected light. A light source, a transmissive light source that irradiates the panel with transmitted light through the stage, a first imaging unit that captures a reflected image irradiated with the reflected light from the reflected light source, and a transmission that is transmitted with the transmitted light from the transmissive light source A second image pickup means for capturing an image; an image control unit that receives the video signal from the first image pickup means and the video signal from the second image pickup means and processes these two types of video signals; It is what you have.

  According to the defect detection apparatus having such a pattern, the reflected image obtained by the reflected light from the reflected light source is taken into the first imaging means, and the transmitted image obtained by the transmissive light source is taken into the second imaging means. By processing the video signal from the first imaging means and the video signal from the second imaging means in the control unit, it becomes possible to detect a pattern defect.

  The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is a block diagram showing an outline of a pattern defect detection apparatus for carrying out a pattern defect detection method according to the present embodiment. This apparatus includes a stage 30 made of a transparent glass plate. A transparent panel 31 on which a pattern is formed is placed on the stage 30. That is, the panel 31 constitutes a work.

  A reflection light source 33 for irradiating the panel 31 on the stage 30 with reflected light is disposed obliquely above the stage 30. In front of the reflected illumination light 34 from the reflected light source 33 in the optical axis direction, a half mirror 35, an optical filter 36, and a half mirror 32 are arranged. A second imaging camera 37 is disposed above the half mirror 32, and a first imaging camera 38 is disposed above another half mirror 35. The pair of imaging cameras 37 and 38 are respectively connected to an image control unit 39, and video signals from the first imaging camera 38 and the second imaging camera 37 are processed by the image control unit 39. Yes. The image control unit 39 is connected to a monitor 40 comprising a display device. The stage 30 is adjusted by the controller 41 in the X-axis direction, the Y-axis direction, and the Z-axis direction. A transmission light source 42 is disposed below the stage 30, and transmitted light 43 from the transmission light source 42 passes through the stage 30 and illuminates the panel 31 from below. A control computer 45 is connected to the image processing unit 39.

  Thus, in the present embodiment, the XYZ stage 30 is a hollow or glass stage that is transparent to the observation light. In addition to the reflected light source 33 that emits the reflected illumination light 34, the illumination is provided with a transmissive light source 42 that irradiates the stage 30 with transmitted light 43 from below. For the defect detected by the defect inspection, the stage 30 is moved to the defect position, the objective lens is set to an arbitrary magnification, and the reflected observation image obtained by using the reflected light 34 from the reflected light source 33 is converted into a half mirror 32. Is reflected by the half mirror 35 through the optical filter 36 and taken into the first imaging camera 38 for acquisition. Next, the reflected illumination light 34 from the reflected light source 33 is blocked, the transmitted light 43 is irradiated from below using the transmitted light source 42, and the transmitted light is irradiated from the lower surface of the panel 31 to obtain a transmitted observation image. Then, the transmission observation image is transmitted through the half mirror 32, and the transmission observation image is taken into the second imaging camera 37. The camera used for image acquisition may be either 37 or 38.

  The above-described operation is performed in the same manner for a defect-free position having no defect, and a reflection observation image and a transmission observation image of the position having the same shape (defect position) having no defect are acquired. The defect-free position is moved to an integral multiple of the pixel size, for example, a position adjacent to one pixel in both XY directions.

  FIG. 2 shows a reflection image obtained by such an operation, and is an image captured by the first imaging camera 38. On the other hand, FIG. 3 shows a transmission image obtained by irradiating the panel 31 with light from below using the transmission light 43 from the transmission light source 42, and the second imaging camera 37. Shows the observations taken in. That is, here, a reflection observation image and a transmission observation image are acquired for one defect, and the defect is detected.

  FIG. 4 shows the entire process of the defect detection method using these two types of observation images, and shows the control operation by the control computer 45. In this operation, the stage 30 is moved to the defect position by adjusting the position of the stage 30 in the X-axis direction and the Y-axis direction, and then the reflected light observation image is acquired by the first imaging camera 38, and then the second imaging camera. 37, a transmitted light observation image is acquired. Thereafter, the stage 30 is moved to a defect-free position by adjusting the position of the stage 30 in the X-axis direction and the Y-axis direction, a reflected light observation image is obtained again by the first imaging camera 38, and the transmitted light is transmitted by the second imaging camera 37. Obtain an observation image.

  FIG. 5 shows an operation of classifying defects using a reflected light observation image, a transmitted light observation image at a defect position, a reflected light observation image at a defect-free position, and a transmitted light observation image. That is, here, first, the presence / absence of a foreign object is determined from the reflected light observation image of the defect position. Here, when it is determined that there is no foreign matter, a determination of a short circuit is performed, and when the determination of a short circuit is Yes, it is recognized as a short defect. On the other hand, when it is determined No in the short determination, an open determination is performed to determine whether there is an open defect.

  If it is determined by the observation using the reflected light observation image that a foreign object is present, a short determination is performed using the transmitted light observation image at the defect position. If the determination is Yes, a short defect with a foreign object is determined. And On the other hand, if it is determined No in the short determination, an open determination is performed. If it is determined Yes here, it is determined as an open defect with a foreign object, and if it is determined No, it is determined as a foreign object. To do.

  FIG. 6 shows operations of the classification of the presence / absence of a foreign substance in FIG. 5, the identification when there is no foreign substance, and the identification when there is no foreign substance and there is no short circuit. This will be explained step by step.

  In the classification of the presence / absence of a foreign substance shown in FIG. 6A, a defective part is extracted, followed by feature extraction of the defective part, and further compared with a foreign substance database. Then, a comparison is made based on whether or not it is similar to the foreign matter data in the comparison with the database. On the other hand, when it is determined No, it is determined as a defect having no foreign matter.

  FIG. 6B shows a subroutine for determining a defect having no foreign matter. The defect part is extracted, the defect part is extracted, and compared with a short defect database. By comparing with such a database, it is discriminated whether it is similar to a short defect, and in the case of Yes, it is determined as a short defect. On the other hand, in the case of No, it is determined that there is no foreign object short circuit defect.

  Next, FIG. 6C shows discrimination of defects without foreign matter and shorts. The defect part is extracted, the defect part is extracted, and then compared with the open defect database. In this comparison, it is determined whether or not the defect is similar to the open defect. If the answer is Yes, the defect is determined as an open defect. If the answer is No, the defect is determined as another defect.

  FIG. 10 shows the details of the classification flow using the transmission image of the foreign matter adhesion defect. Here, the gradation of the wiring pattern is set, and a block of the wiring pattern is created from the gradation. Then, a non-continuous portion is extracted from the contour, and when there is a non-continuous portion, it is determined as a foreign defect open defect. On the other hand, if it is determined No in the determination of whether or not there is a discontinuous part, it is then determined whether there is a connection between the wirings. If it is determined Yes, there is a foreign object short defect. Is determined. On the other hand, when it is determined No, it is determined as a foreign object.

  Next, the discrimination operation using the reflection observation image shown in FIG. 2 and the transmission observation image shown in FIG. 3 will be specifically described. Assume that an image shown in FIG. 2D is obtained as a reflected light observation image. It is assumed that the image shown in FIG. 3A is obtained when the transmitted light observation image corresponding to this case is acquired. When an area having the same level of transmittance or light gradation is recognized as one island, several blocks 15, 16, and 17 are formed in FIG. 3A. Compared with this map and FIG. 3B which is a transmission observation image of the defect-free position, if the pattern 18 and the pattern 19 are the same tone and integrated, it is determined that there is no short circuit.

  In addition, when the map of FIG. 3C is obtained and blocks 15, 16, and 17 are formed, the patterns 18 and 19 must be integrated with the same tone as compared with the transmission observation image FIG. Judge that it is short-circuited.

  Further, when the map of FIG. 3D is obtained and blocks 15, 16, and 17 are formed, the pattern 18 or 19 that should be one continuous pattern is compared with FIG. 3B that is a transmission observation image of the defect-free position. If each of them is divided, it is determined that they are disconnected.

  Although the present invention has been described above with reference to the illustrated embodiments, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the technical idea of the invention included in the present application.

  The present invention can be used for detecting defects in circuit patterns such as TFTs formed on glass substrates in flat panel displays such as liquid crystal displays, plasma displays, and organic EL displays.

It is a block diagram which shows the structure of the defect detection apparatus of a pattern. It is a top view of the reflection observation image obtained by this pattern defect detection apparatus. It is a top view of the transmission observation image obtained by this pattern defect detection apparatus. It is a flowchart which shows the operation | movement of taking in a reflection observation image and a transmission observation image. It is a flowchart which shows the classification | category operation | movement of a defect. It is a flowchart which shows the operation | movement of classification | category (A) of the presence or absence of a foreign material, discrimination | determination of a defect without foreign matter (B), and discrimination | determination of a defect without foreign matter short (C). It is a flowchart which shows judgment of a foreign material presence short.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 ... Stage, 31 ... Panel (work), 32 ... Half mirror, 33 ... Reflection light source, 34 ... Reflection illumination light, 35 ... Half mirror, 36 ... Optical filter, 37 ... 2nd imaging camera, 38 ... 1st Imaging camera 39 ... Image control unit 40 ... Monitor (display device) 41 ... Controller 42 ... Transmitted light source 43 ... Transmitted light 45 ... Computer for control

Claims (16)

In a pattern defect detection method for detecting a pattern defect formed on a transparent or translucent panel,
A defect detection method for a pattern, characterized in that the type of defect of the pattern is specified using image data based on reflected light and image data based on transmitted light at a position where the defect is found. In a pattern defect detection method for detecting a pattern defect formed on a transparent or translucent panel,
Acquire image data by reflected light at a position where a defect is found, then acquire image data by transmitted light at that position, acquire image data by transmitted light at a position where there is no defect, and transmit the transmitted light at the defect position. A defect detection method for a pattern, characterized in that the type of defect in the pattern is specified by comparing the image data obtained by the above and image data obtained by transmitted light at a position where there is no defect.   3. The pattern defect according to claim 2, wherein, in comparison with image data by transmitted light at a position where there is no defect, the corresponding pattern is not short-circuited when the corresponding pattern is not continuous in the same tone. Detection method.   3. The pattern defect according to claim 2, wherein in comparison with image data obtained by transmitted light at a position where there is no defect, the corresponding pattern is short-circuited when the corresponding pattern is continuous in the same tone. Detection method.   The pattern defect detection method according to claim 2, wherein in comparison with image data by transmitted light at a position where there is no defect, the corresponding pattern is disconnected when disconnected.   It is determined whether or not there is a foreign substance on the panel from the image data by the reflected light, and a short circuit and a disconnection are determined for each of the case where it is determined that there is a foreign substance and the case where there is no foreign substance. The pattern defect detection method according to claim 2, wherein:   The pattern defect detection method according to claim 6, wherein whether or not there is a foreign substance is determined by comparison with a foreign substance database.   The pattern defect detection method according to claim 6, wherein the determination of the short circuit is performed by comparison with a short defect database.   7. The pattern defect detection method according to claim 6, wherein the disconnection is determined by comparison with an open defect database.   When it is determined whether or not there is a foreign object, a block of a pattern is created with a predetermined gradation, and it is determined whether or not there is a non-continuous part from the outline of the block. If there is no discontinuous part, it is determined that the pattern wiring is connected to each other, and a short circuit is determined.If the pattern wiring is not connected to each other, foreign matter is detected. The pattern defect detection method according to claim 7, wherein the pattern defect detection method is determined.   The pattern defect detection method according to claim 1, wherein the detection result is used for processing in a process prior to pattern defect detection or for management of the apparatus.   11. The pattern defect detection method according to claim 1, wherein the detection result is used to correct or remove the pattern defect and the foreign matter. A hollow, transparent, or translucent stage on which a transparent or translucent panel with a pattern is placed;
A reflective light source for irradiating the panel with reflected light on the surface;
A transmissive light source for irradiating the panel with transmitted light through the stage;
First imaging means for capturing a reflected image irradiated with reflected light from the reflected light source;
A second imaging means for capturing a transmitted image transmitted by transmitted light from the transmitted light source;
An image control unit that receives the video signal from the first imaging unit and the video signal from the second imaging unit and processes these two types of video signals;
A pattern defect detection apparatus having   14. The pattern defect detection apparatus according to claim 13, wherein the stage is made of glass that transmits light, and the position thereof can be adjusted in the X-axis direction, the Y-axis direction, and the Z-axis direction.   The pattern defect detection apparatus according to claim 13, wherein the reflected light source is disposed above the stage, and the transmitted light source is disposed below the stage. 14. The pattern defect detection apparatus according to claim 13, wherein reflected light and transmitted light from the panel are respectively guided to the first imaging unit and the second imaging unit by a half mirror.

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